US8333255B2 - High productivity core drilling system - Google Patents

Abstract

High productivity core drilling systems include a drill string, an inner core barrel assembly, an outer core barrel assembly, and a retrieval tool that connects the inner core barrel assembly to a wireline cable and hoist. The drill string comprises multiple variable geometry drill rods. The inner core barrel assembly comprises a non-dragging latching mechanism, such as a fluid-driven latching mechanism that contains a detent mechanism that retains the latches in either an engaged or a retracted position. The inner core barrel assembly also comprised high efficiency fluid porting.

Description

FIELD OF INVENTION

This application generally relates to the field of drilling. In particular, this application discusses a drilling system for drilling core samples that can increase drilling productivity by reducing the amount of time needed to place and retrieve a core sample tube (or sample tube) in a drill string.

BACKGROUND AND RELATED ART

Drilling core samples (or core sampling) allows observation of subterranean formations within the earth at various depths for many different purposes. For example, by drilling a core sample and testing the retrieved core, scientists can determine what materials, such as petroleum, precious metals, and other desirable materials, are present or are likely to be present at a desired depth. In some cases, core sampling can be used to give a geological timeline of materials and events. As such, core sampling may be used to determine the desirability of further exploration in a particular area.

In order to properly explore an area or even a single site, many core samples may be needed at varying depths. In some cases, core samples may be retrieved from thousands of feet below ground level. In such cases, retrieving a core sample may require the time consuming and costly process of removing the entire drill string (or tripping the drill string out) from the borehole. In other cases, a faster wireline core drilling system may include a core retrieval assembly that travels (or trips in and out of) the drill string by using a wireline cable and hoist.

While wireline systems may be more efficient than retracting and extending the entire drill string, the time to trip the core sample tube in and out of the drill string still often remains a time-consuming portion of the drilling process. The slow tripping rate of the core retrieval assembly of some conventional wireline systems may be cause by several factors. For example, the core retrieval assembly of some wireline systems may include a spring-loaded latching mechanism. Often the latches of such a mechanism may drag against the interior surface of the drill string and, thereby, slow the tripping of the core sample tube in the drill string. Additionally, because drilling fluid and/or ground fluid may be present inside the drill string, the movement of many conventional core retrieval assemblies within the drill string may create a hydraulic pressure that limits the rate at which the core sample tube may be tripped in and out of the borehole.

BRIEF SUMMARY OF THE INVENTION

This application describes a high productivity core drilling system. The system includes a drill string, an inner core barrel assembly, an outer core barrel assembly, and a retrieval tool that connects the inner core barrel assembly to a wireline cable and hoist. The drill string comprises multiple variable geometry drill rods. The inner core barrel assembly comprises a latching mechanism that can be configured to not drag against the interior surface of the drill string during tripping. In some instances, the latching mechanism may be fluid-driven and contain a detent mechanism that retains the latches in either an engaged or a retracted position. The inner core barrel assembly also comprises high efficiency fluid porting. Accordingly, the drilling system significantly increases productivity and efficiency in core drilling operations by reducing the time required for the inner core barrel assembly to travel through the drill string.

BRIEF DESCRIPTION OF THE FIGURES

To further clarify the advantages and features of the drilling systems described herein, a particular description of the systems will be rendered by reference to specific embodiments illustrated in the drawings. These drawings depict only some illustrative embodiments of the drilling systems and are, therefore, not to be considered as limiting in scope. The same reference numerals in different drawings represent the same element, and thus their descriptions will be omitted. The systems will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

FIG. 1 is a depiction of some embodiments of a core sample drilling system;

FIGS. 2A and 2B contain different views of some embodiments of an inner core barrel assembly;

FIGS. 3A and 3B depict cross-sectional views of some embodiments of one portion of a core sample drilling system;

FIG. 4 is a cross-sectional view of some embodiments of a portion of a core sample drilling system;

FIGS. 5A-5C are cross-sectional views of some embodiments of a portion of a core sample drilling system in different modes of performance; and

FIGS. 6A-6C are cross-sectional views of some embodiments of a portion of a core sample drilling system in different modes of performance.

DETAILED DESCRIPTION

The following description supplies specific details in order to provide a thorough understanding. Nevertheless, the skilled artisan would understand that the drilling systems and associated methods can be implemented and used without employing these specific details. Indeed, the systems and associated methods can be placed into practice by modifying the systems and associated components and methods and can be used in conjunction with any existing apparatus, system, component, and/or technique conventionally used in the industry. For instance, while the drilling systems are described as being used in a downhole drilling operation, they can be modified to be used in an uphole drilling operation. Additionally, while the description below focuses on a drilling system used to trip a core barrel assembly into and out of a drill string, portions of the described system can be used with any suitable downhole or uphole tool, such as a core sample orientation measuring device, a hole direction measuring device, a drill hole deviation device, or any other suitable downhole or uphole object.

FIG. 1 illustrates some embodiments of a drilling system. Although the system may comprise any suitable component,FIG. 1 shows thedrilling system100 may comprise adrill string110, an inner core barrel assembly comprising aninner core barrel200, an outer core barrel assembly comprising anouter core barrel205, and aretrieval tool300 that is connected to acable310.

The drill string may include several sections of tubular drill rod that are connected together to create an elongated, tubular drill string. The drill string may have any suitable characteristic known in the art. For example,FIG. 1 shows a section ofdrill rod120 where thedrill rod120 may be of any suitable length, depending on the drilling application.

The drill rod sections may also have any suitable cross-sectional wall thickness. In some embodiments, at least one section of the drill rod in the drill string may have a varying cross-sectional wall thickness. For example,FIG. 1 shows adrill string110 in which the inner diameter of thedrill rod sections120 varies along the length of the drill rod, while the outer diameter of the sections remains constant.FIG. 1 also shows that the wall thickness at thefirst end122 of a section of thedrill rod120 can be thicker than the wall thickness near themiddle124 of that section of thedrill rod120.

The cross-sectional wall thickness of the drill rod may vary any suitable amount. For instance, the cross-sectional wall thickness of the drill rod may be varied to the extent that the drill rod maintains sufficient structural integrity and remains compatible with standard drill rods, wirelines, and/or drilling tools. By way of example, a drill rod with an outer diameter (OD) of about 2.75 inches may have a cross-sectional wall thickness that varies about 15% from its thickest to its thinnest section. In another example, a drill rod with an OD of about 3.5 inches may have a cross-sectional wall thickness that varies about 22% from its thickest to its thinnest section. In yet another example, a drill rod with an OD of about 4.5 inches may have a cross-sectional wall thickness that varies about 30% from its thickest to its thinnest section. Nevertheless, the cross-sectional wall thickness of the drill rods may vary to a greater or lesser extent than in these examples.

The varying cross-sectional wall thickness of the drill rod may serve many purposes. One purpose is that the varying wall thickness may allow the inner core barrel to move through the drill string with less resistance. Often, the drilling fluid and/or ground fluid within the drill string may cause fluid drag and hydraulic resistance to the movement of the inner core barrel. However, the varying inner diameter ofdrill string110 may allow drilling fluid or other materials (e.g., drilling gases, drilling muds, debris, air, etc.) contained in thedrill string110 to flow past the inner core barrel in greater volume, and therefore to flow more quickly. For example, fluid may flow past theinner core barrel200 as the inner barrel passes through the wider sections (e.g., near the middle124 of a section120) of thedrill string110 during tripping.

In some embodiments, the drilling system comprises a mechanism for retaining the inner core barrel at a desired distance from the drilling end of the outer core barrel. Although any mechanism suitable for achieving the intended purpose may be used,FIG. 1 shows some embodiments where the retaining mechanism comprises alanding shoulder140 and alanding ring219. Specifically,FIG. 1 shows that thelanding shoulder140 comprises an enlarged shoulder portion on theinner core barrel200. Further,FIG. 1 shows theouter core barrel205 can comprise alanding ring219 that mates with thelanding shoulder140.

The landing ring and landing shoulder may have any feature that allows the inner core barrel to “seat” at a desired distance from the drilling end ofdrill string110. For example, the landing shoulder may be slightly larger than the outer diameter of the inner core barrel and the core sample tube. In another example, the landing ring may have a smaller inner diameter than the smallest inner diameter of any section of drill rod. Thus, the reduced diameter of the landing ring may be wide enough to allow passage of the sample tube, while being narrow enough to stop and seat the landing shoulder of the inner core barrel in a desired drilling position.

The annular space between the outer perimeter of the landing shoulder and the interior surface of the drill string may be any suitable width. In some instances, the annular space may be thin because a thin annular space may allow the sample tube to have a larger diameter. In other instances, though, because a thin annular space may prevent substantial passage of fluid as the inner core barrel trips through the drill string, the landing shoulder may comprise any suitable feature that allows for increased fluid flow past the landing shoulder. In these other instances,FIG. 2B shows that thelanding shoulder140 may have a plurality of flat surfaces orflats145 incorporated into its outer perimeter, giving the outer perimeter of the landing shoulder140 a polygonal appearance. Such flats can increase the average width of the annular space so as to reduce fluid resistance—and thereby increase fluid flow—in both tripping directions.

Thedrill string110 may be oriented at any angle, including between about 30 and about 90 degrees from a horizontal surface, whether for an up-hole or a down-hole drilling process. Indeed, when thesystem100 used with a drilling fluid in a downhole drilling process, a downward angle may help retain some of the drilling fluid at the bottom of a borehole. Additionally, the downward angle may allow the use of a retrieval tool and cable to trip the inner core barrel from the drill string.

The inner core barrel may have any characteristic or component that allows it to connect a downhole object (e.g., a sample tube) with a retrieval tool so that the downhole object can be tripped in or out of the drill string. For example,FIG. 2A shows theinner core barrel200 may include aretrieval point280, an upper core barrel assembly comprising an upper core barrel210 (or in other words a core barrel head assembly), and a lower core barrel assembly comprising alower core barrel240.

Theretrieval point280 of theinner core barrel200 may have any characteristic that allows it to be selectively attached to any retrieval tool, such as an overshot assembly and a wireline hoist. For example,FIG. 2A shows theretrieval point280 may be shaped like a spear point so as to aid the retrieval tool to correctly align and couple with the retrieval tool. In another example, theretrieval point280 may be pivotally attached to the upper core barrel so as to pivot in one plane with a plurality of detent positions. By way of illustration,FIG. 2B shows theretrieval point280 may be pivotally attached to a spearhead base285 of a retrieval tool via a pin290 so a spring-loadeddetent plunger292 can interact with a corresponding part on the spearhead base285.

Theupper core barrel210 may have any suitable component or characteristic that allows the core sample tube to be positioned for core sample collection and to be tripped out of the drill string. For example,FIGS. 3 A and3B show theupper core barrel210 may include an inner sub-assembly230 (or in other words an inner member), an outer sub-assembly270 (or in other words an outer sleeve), afluid control valve212, alatching mechanism220, and aconnection member213 for connecting to the lower core barrel.

Theinner sub-assembly230 and theouter sub-assembly270 may have any component or characteristic suitable for use in an inner core barrel. For instance,FIG. 2B shows some embodiments where the inner and the outer sub-assembly may be configured to allow theinner sub-assembly230 to be coupled to and move axially (or move back and/or forth in the drilling direction) with respect to theouter sub-assembly270.FIG. 2B also shows that theinner sub-assembly230 can be connected to theouter sub-assembly270 via apin227 that passes through a slot232 in theinner sub-assembly230 in a manner that allows theinner sub-assembly230 to move axially with respect to theouter sub-assembly270 for a distance corresponding to the length of the slot232.

In some embodiments, the upper core barrel comprises a fluid control valve. Such a valve may serve many functions, including providing control over the amount of drilling fluid that passes through the inner core barrel during tripping and/or drilling. Another function can include partially controlling the latching mechanism, as described herein.

The fluid control valve may have any characteristic or component consistent with these functions. For example,FIGS. 2B and 3A show that thefluid control valve212 can comprise a fluidcontrol valve member215 and avalve ring211. Thevalve member215 may be coupled to theouter sub-assembly270 by any known connector, such aspin216. Thepin216 may travel in aslot214 of thevalve member215 so that thevalve member215 can move axially with respect to both theinner sub-assembly230 and theouter sub-assembly270. The movement of thevalve member215 relative to theinner sub-assembly230 allows thefluid control valve212 to be selectively opened or closed by interacting with thevalve ring211. For example,FIG. 3A shows thefluid control valve212 in an open position where thevalve member215 has traveled past thevalve ring211, to one extent of theslot214. Conversely,FIG. 3B shows thefluid control valve212 in an open position where thevalve member215 is retracted to another extent of theslot214. The fluid control valve inFIG. 3B is in a position ready to be inserted into the drill string where it can allow fluid to flow from the lower core barrel to the upper core barrel.

In some embodiments, theupper core barrel210 can contain aninner channel242 that allows a portion of the drilling fluid to pass through theupper core barrel210. While fluid ports may be provided along the length of theinner core barrel200 as desired,FIGS. 2A and 3B showfluid ports217 and217B that provide fluid communication between theinner channel242 and the exterior ofinner core barrel200. Thefluid ports217 and217B may be designed to be efficient and to allow fluid to flow through and past portions ofinner core barrel200 where fluid flow may be limited by geometry or by features and aspects ofinner core barrel200. Similarly, any additional fluid flow features may be incorporated as desired, i.e., flats machined into portions of inner core barrel.

FIG. 3A shows some embodiments where thefluid control valve212 is located within theinner channel242. In such embodiments, a drilling fluid supply pump (not shown) may be engaged to deliver fluid flow and pressure to generate fluid drag across thevalve member215 so as to push thevalve member215 to engage and/or move past thevalve ring211.

In some embodiments, the upper core barrel also comprises a latching mechanism that can retain the core sample tube in a desired position with respect to the outer core barrel while the core sample tube is filled. In order to not hinder the movement of the inner core barrel within the drill string, the latching mechanism can be configured so that the latches do not drag against the drill string's interior surface. Accordingly, this non-dragging latching mechanism can be any latching mechanism that allows it to perform this retaining function without dragging against the interior surface of the drill string during tripping. For instance, the latching mechanism can comprise a fluid-driven latching mechanism, a gravity-actuated latching mechanism, a pressure-activated latching mechanism, a contact-actuated mechanism, or a magnetic-actuated latching mechanism. Consequently, in some embodiments, the latching mechanism can be actuated by electronic or magnetic sub-systems, by valve works driven by hydraulic differences above and/or below the latching mechanism, or by another suitable actuating mechanism.

The latching mechanism may also comprise any component or characteristic that allows it to perform its intended purposes. For example, the latching mechanism may comprise any number of latch arms, latch rollers, latch balls, multi-component linkages, or any mechanism configured to move the latching mechanism into the engaged position when the landing shoulder of the inner core barrel is seated against the landing ring.

By way of non-limiting example,FIGS. 2B and 3A show some embodiments of thelatching mechanism220 comprising at least onepivot member225 that is pivotally coupled to theouter sub-assembly270 by a connector, such aspin227.FIGS. 2B and 3A also show thelatching mechanism220 can include at least onelatch arm226 that is coupled to theinner sub-assembly230 by a connector (such as pin228) so that the latch arm orarms226 may be retracted or extended from theouter sub-assembly270.FIG. 2B shows thelatch arm226 can comprise anengagement flange229, or a surface configured to frictionally engage the interior surface of the drill string when the latching mechanism is in an engaged position. For example,FIG. 3A shows that when in an engaged position, thelatch arms226 may extend out of and/or away from theouter sub-assembly270. Conversely, when in a retracted position (as shown inFIG. 5C), thelatch arms226 may not extend outside the outer diameter of theouter sub-assembly270.

In some embodiments, the latching mechanism may also comprise a detent mechanism that helps maintain the latching mechanism in an engaged or retracted position. The detent mechanism may help hold the latch arms in contact with the interior surface of the drill string during drilling. The detent mechanism may also help the latch arms to stay retracted so as to not contact and drag against the interior surface of the drill string during any tripping action.

The detent mechanism may contain any feature that allows the mechanism to have a plurality of detent positions.FIG. 3B shows some embodiments where thedetent mechanism234 comprises aspring237 with aball238 at each end. Thedetent mechanism234 is located in theinner sub-assembly230 and cooperates withdetent positions235 and236 in theouter sub-assembly270 to hold the latching mechanism in either an engaged position, as when thedetent mechanism234 is in an engageddetent position235, or a retracted position, as when thedetent mechanism234 is in a retracteddetent position236.

In some preferred embodiments, the latching mechanism may cooperate with the fluid control valve so as to be a fluid-driven latching mechanism. Accordingly, thefluid control valve212 can operate in conjunction with thelatching mechanism220 so as to allow theinner core barrel200 to be quickly and efficiently tripped in and out of thedrill string110. The latching mechanism and the fluid control valve may be operatively connected in any suitable manner that allows the fluid control valve to move the latching mechanism to the engaged position as shown inFIGS. 5A-6C, as described in detail below.

FIG. 4 illustrates some embodiments of thelower core barrel240. Thelower core barrel240 may include any component or characteristic suitable for use with an inner core barrel. In some embodiments, as shown inFIG. 4, the lower core barrel may comprise at least oneinner channel242,check valve256,core breaking apparatus252, bearingassembly255,compression washer254, and coresample tube connection258.

FIG. 4 shows that theinner channel242 can extend from the upper core barrel through thelower core barrel240. Among other things, the inner channel can increase productivity by allowing fluid to flow directly through the lower core barrel. The inner channel may have any feature that allows fluid to flow through it. For example,FIG. 2B shows theinner channel242 may comprise a hollow spindle251 that runs from theupper core barrel210 to thelower core barrel240.

According to some embodiments, the lower core barrel comprises acheck valve256 that allows fluid to flow from the core sample tube to the inner channel, but does not allow fluid to flow from the inner channel to the core sample tube. Accordingly, the check valve may allow fluid to pass into the inner channel and then through the inner core barrel when the inner core barrel is being tripped into the drill string and when core sample tube is empty. In this manner, fluid resistance can be lessened so the inner core barrel can be tripped into the drill string faster and more easily. On the other hand, when the inner core barrel is tripped out of the drill string, the check valve can prevent fluid from pressing down on a core sample contained in core sample tube. Accordingly, the check valve may prevent the sample from being dislodged or lost. And when the check valve prevents fluid from passing through the lower core barrel and into the core sample tube, the fluid may be forced to flow around the outside of the core sample tube and the lower core barrel. Although any unidirectional valve may serve as the check valve,FIG. 4 shows some embodiments where thecheck valve256 comprises aball valve259.

In some embodiments, thelower core barrel240 may comprise a bearing assembly that allows the core sample tube to remain stationary while the upper core barrel and drill string rotate. The lower core barrel may comprise any bearing assembly that operates in this manner. In the embodiments shown inFIG. 4, the bearingassembly255 comprises ball bearings that allow anouter portion257 of thelower core barrel240 to rotate with the drill string during drilling operations, while maintaining the core sample tube in a fixed rotational position with respect to the core sample.

The lower core barrel may be connected to the core sample tube in any suitable manner.FIG. 4 shows some embodiments where thelower core barrel240 is configured to be threadingly connected to the inner tube cap275 (shown inFIG. 2B) and/or the core sample tube by a coresample tube connection258, which is coupled to the bearingassembly255.

FIG. 4 also shows some embodiments where thelower core barrel240 contains a core breaking apparatus. The core breaking apparatus may be used to apply a moment to the core sample and, thereby, cause the core sample to break at or near the drill head (not shown) so the core sample can be retrieved in the core sample tube. While thelower core barrel240 may comprise any core breaking apparatus,FIG. 4 shows some embodiments where thecore breaking apparatus252 comprises aspring261 and abushing263 that can allow relative movement of the core sample tube and thelower core barrel240.

In some embodiments, the lower core barrel may also comprise one or more compression washers that restrict the flow of drilling fluid once the core sample tube is full, or once a core sample is jammed in the core sample tube. The compression washers (254 shown inFIG. 4) can be axially compressed when the drill string and the upper core barrel press in the drilling direction, but the core sample tube does not move axially because the sample tube is full or otherwise prevented from moving downwardly with the drill string. This axial compression causes the washers to increase in diameter so as to reduce, and eventually eliminate, any space between the interior surface of the drill string and the outer perimeter of the washers. As the washers reduce this space, they can cause an increase in drilling fluid pressure. This increase in drilling fluid pressure may function to notify an operator of the need to retrieve the core sample and/or the inner core barrel.

FIGS. 5A-6C illustrate some examples of the function of theinner core barrel200 during tripping and drilling and the function of some embodiments of both thedetent mechanism234 and the fluid-drivenlatching mechanism220.FIG. 5A depicts thedetent mechanism234 in an intermediary position, as may be the case when thelatching mechanism220 is manually placed in a retracted position in preparation for insertion into the drill string.FIG. 5B shows that when thelatch arms226 are in an engaged position, thepivot member225 is extended to force thelatch arms226 to remain outward (as also shown inFIG. 3A). On the contrary, when thelatch arms226 are in a retracted position, as shown inFIG. 5C, thepivot member225 can be rotated such that thelatch arms226 may be retracted into theupper core barrel210.

As described above, theinner sub-assembly230 can move axially with respect to theouter sub-assembly270. In some embodiments, this movement can cause the latching mechanism to move between the retracted and the engaged positions as illustrated inFIGS. 5A-5C, where the movement of theinner sub-assembly230 with respect to theouter sub-assembly270 may change the position of thelatch arms226. Thepin228 holding thelatch arms226 can be connected only to theinner sub-assembly230 and thepin227 holding thepivot member225 can be connected to theouter sub-assembly270. Thus, when theouter sub-assembly270 moves axially with respect to theinner sub-assembly230 so as to cover less of the of theinner sub-assembly230, the distance between the two pins (pin228 and pin227) can increase and thepivot member225 can rotate. As a result, thelatch arms226 may partially or completely move into theouter sub-assembly270 and thedetent mechanism234 can move from the engageddetent position235 to the retracted detent position236 (as shown inFIG. 5C). On the contrary, when theouter sub-assembly270 moves axially so as to cover more of theinner sub-assembly230, the distance between the two pins (pins228 and227) can decrease and thelatch arms226 may be forced out of theouter sub-assembly270 into an engaged position (as shown inFIG. 5B).

FIGS. 6A-6C show some examples of how thefluid control valve212 can function.FIG. 6A shows thefluid control valve212 in an open position so that fluid can flow from thelower core barrel240, through theinner channel242, past thefluid ring211, past thefluid control valve212, and through thefluid ports217B to the exterior of theinner core barrel200. With thefluid control valve212 in an open position, thelatching mechanism220 can be in a retracted position and ready for insertion into the drill string. In this open position shown inFIG. 6A, the fluid can flow from thelower core barrel240 to theupper core barrel210, but fluid pressure forces thevalve member215 towards thefluid ring211 and causes the fluid control valve to press against thefluid ring211 and prevent fluid flow.

When the landing shoulder of the inner core barrel reaches the landing ring in the drill string, the inner core barrel can be prevented from moving closer to the drilling end of the outer core barrel. Because the landing shoulder can be in close tolerance with the interior surface of the drill string, drilling fluid may be substantially prevented from flowing around thelanding shoulder140. Instead, the drilling fluid can travel through the inner core barrel200 (e.g., viafluid ports217B and the inner channel242). Thus, the fluid can flow and press against thevalve member215. Theslot214 may then allow thevalve member215 to move axially so as to press into and past thefluid ring211 until theslot214 engagespin216.FIGS. 6B and 3A show that at this point, thefluid control valve212 may again be in an open position below thefluid ring211. Where thedetent mechanism234 is in an intermediary position (as shown inFIG. 5A), theinner sub-assembly230 may be moved when thevalve member215 pulls on thepin216 that is attached to theinner sub-assembly230. Thus, fluid pressure can cause thevalve member215 to move past thefluid ring211 and, thereby, move theinner sub-assembly230 and thedetent mechanism234 so that thelatching mechanism220 moves into and is retained in the engaged position.

FIGS. 5B and 6B illustrate some embodiments of theinner core barrel200 with thelatching mechanism220 in the engaged position (i.e., ready for drilling). As shown inFIG. 5B, thedetent mechanism234 can be held in the engageddetent position235. And as shown inFIG. 6B, during drilling thefluid control valve212 can be held in an open position with thevalve member215 pushed below thefluid ring211 by the fluid pressure.

Once the core sample tube is filled as desired, the drilling process may be stopped and the core sample can be tripped out of the drill string. To retrieve the core sample, theretrieval point280 is pulled towards earth's surface by aretrieval tool300 connected to awireline cable310 and hoist (not shown). The pulling force on the retrieval point280 (and hence the pulling force on the outer sub-assembly270) may be resisted by the engaged latching mechanism (e.g., mechanism220) and the weight of the core sample in the core sample tube. These resisting forces may cause theinner sub-assembly230 to move with respect to theouter sub-assembly270 so that thedetent mechanism234 moves from the engaged detent position235 (as shown inFIG. 5B) to the retracted detent position236 (as shown inFIG. 5C). The movement of theinner sub-assembly230 forces thepin216 to move away from thefluid ring211. As theslot214 in thevalve member215 is caught by thepin216, thefluid control valve212 moves into a closed position where thevalve member215 is seated in the fluid ring211 (as shown inFIG. 6C). And as the inner core barrel is tripped out of the drill string, downward fluid pressure may prevent thefluid control valve212 from opening upwardly.

As mentioned above, the movement of theinner sub-assembly230 may force thelatching mechanism220 into a retracted position, as shown inFIG. 6C. In the retracted position, thelatching mechanism220 does not drag or otherwise resist extraction of theinner core barrel200 from the drill string. Thus, the fluid-driven latching mechanism greatly reduces the time required to retrieve a core sample. Once theinner core barrel200 is tripped out of the drill string and the core sample is removed, the inner core barrel can be reset, as illustrated byFIGS. 5A and 6A, to be placed into drill string to retrieve another core sample.

In some variations of the described system, one or more of the various components of the inner core barrel may be incorporated with a variety of other downhole or uphole tools and/or objects. For instance, some form of the non-dragging latching mechanism, such as the fluid-driven latching mechanism with the detent mechanism, may be incorporated with a ground or hole measuring instrument or a hole conditioning mechanism. By way of example, any in-hole measuring instrument assembly may comprise a fluid-driven latching mechanism, such as that previously described. In this example, the assembly may be tripped into the drill string and stopped at a desired position (e.g., at the landing ring). Then, as fluid applies pressure to the fluid control valve in the assembly, the latching mechanism can be moved to the engaged position in a manner similar to that described above.

The embodiments described in connection with this disclosure are intended to be illustrative only and non-limiting. The skilled artisan will recognize many diverse and varied embodiments and implementations consistent with this disclosure. Accordingly, the appended claims are not to be limited by particular details set forth in the above description, as many apparent variations thereof are possible without departing from the spirit or scope thereof.

Claims (32)

1. A downhole tool assembly configured to be tripped through a drill string, comprising:

a core barrel head assembly comprising an outer sleeve;

a non-dragging latching mechanism configured to be tripped into a drill string without dragging against an interior surface of the drill string, wherein the latching mechanism is configured to selectively move between an engaged position and a retracted position, wherein when in said engaged position, at least a portion of said latching mechanism extends outward of said outer sleeve; and

a detent mechanism configured to selectively lock said latching mechanism in said retracted position as said core barrel head assembly is tripped into the drill string, wherein said detent mechanism comprises:

a first pair of opposed recesses extending into an inner surface of said outer sleeve;

a second pair of opposed recesses extending into said inner surface of said outer sleeve, wherein said second pair of opposed recesses is spaced distally with respect to said first pair of opposed recesses;

a pair of balls configured to be selectively biasably received within said first pair of opposed recesses when said latching mechanism is in said retracted position and within said second pair of opposed recesses when said latching mechanism is in said engaged position; and

a spring positioned therebetween said pair of balls and configured to selectively bias said pair of balls outwardly toward the one pair of the respective said first or second pairs of opposed recesses.

2. The downhole tool assembly ofclaim 1, wherein said latching mechanism comprises a fluid-driven latching mechanism.

3. The downhole tool assembly ofclaim 1, wherein said detent mechanism is configured to selectively retain said latching mechanism in said engaged position.

4. The downhole tool assembly ofclaim 1, further comprising a retrieval portion coupled to said core barrel head assembly.

5. The downhole tool assembly ofclaim 4, wherein said latching mechanism is configured to be moved into said engaged position by fluid pressure and configured to be moved to said retracted position by a force on a retrieval portion.

6. The downhole tool assembly ofclaim 1, wherein said core barrel head assembly further comprises an inner member moveably coupled to said outer sleeve.

7. The downhole tool assembly ofclaim 6, wherein said detent mechanism is configured to selectively prevent movement of said outer sleeve relative to said inner member.

8. The downhole tool assembly ofclaim 7, wherein said outer sleeve has a longitudinal axis, and wherein said first pair of opposed recesses is spaced longitudinally with respect the said second pair of opposed recesses.

9. The downhole tool assembly ofclaim 8, wherein said spring is positioned substantially transverse to said longitudinal axis of said outer sleeve.

10. The downhole tool assembly ofclaim 1, wherein said latching mechanism comprises:

a latch arm; and

a pin;

wherein axial movement of said pin causes said latch arm to pivot between said engaged position and said retracted position.

11. The downhole tool assembly ofclaim 1, wherein said latching mechanism comprises one of latch arms, latch balls, latch rollers, or multi-component linkages.

12. A core barrel head assembly configured to be tripped through a drill string to an outer core barrel having a landing ring, comprising:

an inner member;

an outer sleeve moveably coupled to the inner member, the outer sleeve having an outer diameter,

a latching mechanism configured to selectively move between an engaged position and a retracted position as the outer sleeve moves relative to the inner member, wherein, when in the engaged position, at least a portion of the latching mechanism extends outward of the outer sleeve, and wherein, when in the retracted position, the latching mechanism is constrained within the outer diameter of the outer sleeve; and

a detent mechanism configured to selectively prevent movement of the outer sleeve relative to the inner member and thus selectively lock the latching mechanism in the retracted position until the distal end of the outer sleeve of the core barrel head assembly is positioned proximate the landing ring whereupon the inner member is forced to move axially and distally a predetermined distance relative to the outer sleeve to selectively lock the latching mechanism in the engaged position.

13. The core barrel head assembly as recited inclaim 12, wherein the detent mechanism comprises:

at least one recess extending into an inner surface of the outer sleeve; and

at least one feature adapted to extend from the inner member into the at least one recess of the outer sleeve.

14. The core barrel head assembly as recited inclaim 13, wherein the detent mechanism further comprises a spring that biases the at least one feature radially outward toward the at least one recess.

15. The core barrel head assembly as recited inclaim 14, wherein the at least one feature comprises a ball.

16. The core barrel head assembly as recited inclaim 15, wherein the latching mechanism further comprises a latch pin coupled to the latch arm, the latch pin being configured to pivot the latch arm between the retracted position and the engaged position as the outer sleeve moves relative to the inner member.

17. The core barrel head assembly as recited inclaim 13, wherein the detent mechanism further comprises at least a second recess extending into the inner surface of the outer sleeve, the second recess being axially spaced from the at least one recess.

18. The core barrel head assembly as recited inclaim 12, wherein the latching mechanism comprises a latch arm adapted to pivot from between the retracted position and the engaged position.

19. The core barrel head assembly as recited inclaim 12, wherein the detent mechanism comprises:

a first pair of opposed recesses extending into an inner surface of the outer sleeve;

a second pair of opposed recesses extending into said inner surface of the outer sleeve, wherein the second pair of opposed recesses is spaced distally with respect to the first pair of opposed recesses; and

a pair of balls configured to be selectively biasably received within the first pair of opposed recesses when the latching mechanism is in the retracted position and within the second pair of opposed recesses when the latching mechanism is in the engaged position.

20. The core barrel head assembly as recited inclaim 19, wherein the detent mechanism further comprises a spring a spring mounted therein the inner member and configured to selectively bias the pair of balls outwardly toward the one pair of the respective first or second pairs of opposed recesses.

21. A drilling system for interfacing with a drill string having an outer core barrel defining a landing ring, the drilling system comprising:

a core barrel head assembly configured to be tripped to be tripped through the drill string to the outer core barrel, comprising:

an outer sleeve having a distal end and an outer diameter;

a non-dragging latching mechanism configured to be tripped into the drill string without dragging against an interior surface of the drill string, wherein the latching mechanism is configured to selectively move between an engaged position and a retracted position, wherein when in the engaged position, at least a portion of the latching mechanism extends outward of the outer diameter of the outer sleeve, and wherein, when in the retracted position, the latching mechanism is constrained within the outer diameter of the outer sleeve;

a retrieval portion coupled to the outer sleeve and configured to be connected to a wireline cable; and

a detent mechanism configured to selectively lock the latching mechanism in the retracted position until the distal end of the outer sleeve of the core barrel head assembly is positioned proximate the landing ring.

22. The drilling system as recited inclaim 21, wherein the retrieval portion comprises a spearhead that is moveably coupled to the outer sleeve.

23. The drilling system as recited inclaim 21, further comprising

at least one drill rod adapted to be coupled to the outer core barrel;

wherein the at least one drill rod has a varying inner diameter and a uniform outer diameter.

24. The drilling system as recited inclaim 21, further comprising:

a core sample tube; and

an inner channel extending from the core barrel head assembly to the core sample tube.

25. The drilling system ofclaim 24, where in the inner channel comprises a check valve that is configured to allow fluid to pass from the core sample tube to the inner channel but not from the inner channel into the core sample tube.

26. The inner drilling system ofclaim 24, wherein the core barrel head assembly comprises ports that are hydraulically connected to the inner channel and configured to permit fluid to pass from the inner channel to the exterior of the core barrel head assembly.

27. The drilling system as recited inclaim 24, further comprising:

an inner member moveably coupled to the outer sleeve; and

wherein the detent mechanism is configured to selectively prevent movement of the outer sleeve relative to the inner member and thus selectively lock the latching mechanism in the retracted position until the inner member is forced to move axially and distally a predetermined distance relative to the outer sleeve whereupon the latching mechanism is selectively locked in the engaged position.

28. The drilling system as recited inclaim 27, wherein the detent mechanism comprises:

at least one recess extending into an inner surface of the outer sleeve; and

at least one feature adapted to extend from the inner member into the at least one recess of the outer sleeve and prevent relative movement between the inner member and the outer sleeve.

29. The drilling system as recited inclaim 27, wherein the detent mechanism comprises:

a first pair of opposed recesses extending into an inner surface of the outer sleeve;

a second pair of opposed recesses extending into the inner surface of the outer sleeve, wherein the second pair of opposed recesses is spaced distally with respect to the first pair of opposed recesses; and

a pair of balls configured to be selectively biasably received within the first pair of opposed recesses when the latching mechanism is in the retracted position and within the second pair of opposed recesses when the latching mechanism is in the engaged position.

30. The drilling system as recited inclaim 29, wherein the detent mechanism further comprises a spring mounted therein the inner member and configured to selectively bias the pair of balls outwardly toward the one pair of the respective first or second pairs of opposed recesses.

31. The drilling system as recited inclaim 21, wherein the detent mechanism is configured to selectively lock the latching mechanism in the retracted position irrespective of a position of the retrieval portion relative to the outer sleeve.

32. The drilling system as recited inclaim 21, wherein, when in the retracted position, the latching mechanism is constrained within the outer diameter of the outer sleeve.

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